All water cooled engines of either the gasoline or diesel fuel type use a radiator to dissipate the heat adsorbed by the engine jacket coolant. Generally, radiators consist of thin walled tubes, or passages of honeycomb form, through which the coolant is conducted, and across which an air stream is induced, either by the motion of the vehicle if the engine is installed in a vehicle, and/or by a fan. Conventional radiators as used in most automobiles and many trucks are what is called the single pass, vertical flow type or single pass, cross flow type. Thus, the coolant makes a single pass through the radiator core. In the vertical flow type, hot coolant from the engine enters at the top of the radiator and exits at the bottom of the radiator with the coolant temperature having been reduced. In a cross flow radiator, hot coolant from the engine enters at the top of one end of the radiator, flows in a lateral direction through the core, and exits at the bottom of the opposite end of the radiator. Cooling systems which employ the foregoing single pass radiators are usually of the high flow cooling type, that is, the hot coolant from the engine flows rapidly through the radiator resulting in a temperature drop of the coolant of perhaps about 10 degrees F. In some applications, this rather small drop in coolant temperature is not satisfactory for ideal engine performance. As a result, low flow cooling systems have been developed in which the temperature drop across the radiator is significantly greater, about 80 degrees F., resulting in optimum engine performance in certain applications.
Although there are a number of differences between high flow and low flow cooling systems, a basic difference is in the type of radiator employed. As previously mentioned, whereas high flow cooling systems customarily employ a single pass radiator, low flow cooling systems employ so-called multi-pass radiators of various types. A typical two pass, side to side, vertical flow radiator, has a top and bottom tank and radiator core positioned between the two tanks as in a typical single pass vertical flow radiator. However, in the two pass radiator, both the coolant inlet and outlet connections are located either at the top end tank or at the bottom end tank as contrasted with the single pass vertical flow radiator where the coolant inlet connection is usually at the top end tank and the coolant outlet connection is usually at the bottom end tank. In a typical two pass, side-to-side vertical flow radiator, hot coolant enters at one side of the bottom end tank, flows upwardly through one half of the radiator core to the top end tank, and the proceeds in a downward direction through the other half of the radiator core to the bottom end tank and then exits from the bottom end tank back to the engine. In all multi-pass radiators, it is necessary to employ a baffle plate to effectively divide the radiator core. Thus, in the two-pass, side-to-side vertical-flow radiator just described, a baffle plate is located in the bottom end tank and effectively divides the tank into two tanks. This construction directs coolant flow up the core in one half the tubes of the core and down the core in the other one half of the tubes. There are other types of multi-pass radiators available. For example, there is a so-called three-pass, side-to-side, vertical flow radiator with a baffle in both the top and bottom end tanks. The coolant inlet and one baffle plate are located in the top end tank and the coolant outlet and an additional baffle are located in the bottom end tank. Thus the coolant makes three vertical passes in its flow through this type of radiator. There are also multi-pass cross flow radiators which cause the coolant to make several passes through the radiator core. However, no matter which particular type of multi-pass radiator is used for cooling, baffle plates are employed to separate inlet and outlet coolant flows.
It is important in multi-pass radiators that the separation of inlet and outlet coolant flows be as complete as possible. For example, it has been determined that a leak equivalent to a one-eighth inch hole between the inlet and outlet flows could decrease radiator performance substantially and be a source of overheating problems. Thus, a number of different techniques have been employed to seal the tank end baffles. Some radiator baffle plates are sealed at the radiator core with a flat gasket, the gasket being attached to the core header plate with what is called a "RTV" sealant. RTV sealants are typically described as high temperature gasket forming compounds employing silicones. A seal is made as the baffle compresses the gasket when the end tank is installed to the radiator core. In the construction of most multi-pass radiators, the baffle plate is sealed at the radiator core by inserting the free edge of the baffle plate into an elongated channel which is soldered or welded to the radiator core header plate. Such channel is usually V-shaped (called a "V-clip") or U-shaped. Prior to inserting the baffle plate into the V-clip, the clip is filled with an RTV sealant and then the baffle plate is inserted into the clip resulting in a seal along the entire length of the baffle plate. RTV sealant is also applied to a small area in the interior of the tank where the top end of the plate meets the radiator casing flange and tank flange. In a still different construction, the baffle plate is sealed to the radiator core by means of a thick, slotted gasket. Again, RTV sealant is used to hold the gasket in place and seal the baffle in the slot in the gasket. However, most multi-pass radiators designs use the baffle plate welded to the tank and a V-groove or "clip" welded to the header. The clip retains a bead of RTV sealant that provides the seal. As noted earlier, RTV sealant is also applied to a small area in the tank interior where the top end of the baffle plate meets the juncture of the radiator casing flange and tank flange.
In repairing multi-pass radiators, it is usually necessary that the end tanks be removed from the core and such removal of course destroys the seals formed by the RTV sealant. When the radiator core and end tanks are reassembled, it is of course necessary that the baffle plate be resealed as previously described. However, before reassembling the components of the radiator, it is extremely important that both the baffle plate and the clip be thoroughly cleaned in the area where the RTV sealant is to be applied. The surfaces must be wire brushed or cleaned with steel wool, followed by a solvent wash and then all parts are thoroughly dried before applying the RTV sealant. It is also important that excessive amounts of RTV sealant not be used since this could result in portions of the sealant breaking away and resulting in plugged coolant passages, particularly the radiator tubes. Moreover, after assembly of the sections using the RTV sealant, the sealant must cure for 8-10 hours or, curing can be speeded up by applying moderate heat (about 250 degrees F.) for a period of perhaps thirty minutes to one hour. It is thus seen that proper baffle sealing is critical to good engine cooling performance. It has also been seen that repairing a radiator which necessitates resealing these critical areas is a time consuming operation and must be performed in a skilled manner, otherwise leakage will certainly occur. Thus, there are a number of disadvantages to the current techniques employed in sealing baffle plates in multi-pass radiators.
Accordingly, it is a principal object of this invention to provide an improved baffle plate seal in multi-pass radiators.
It is a further object of this invention to provide an improved baffle plate seal in multi-pass radiators that eliminates the need for RTV sealants.
It is a still further object of this invention to provide an improved baffle seal in multi-pass radiators which will provide a leak-free connection between the V-clip and the baffle, as well as the void where the top end of the baffle plate meets the radiator casing flange and tank flange.
It is a still further object of this invention to provide a formed gasket of special construction which will provide an improved baffle plate seal in multi-pass radiators, the formed gasket providing a leak-free connection not only between the clip and baffle, but in the void where the top end of the baffle plate meets the radiator casing flange and tank flange.
These and other objects of the invention will be apparent from the following description and claims.